Peripheral axotomy induces long-term c-Jun amino-terminal kinase-1 activation and activator protein-1 binding activity by c-Jun and junD in adult rat dorsal root ganglia In vivo.
One of the earliest documented molecular events after sciatic nerve injury in adult rats is the rapid, long-term upregulation of the immediate early gene transcription factor c-Jun mRNA and protein in lumbar dorsal root ganglion (DRG) neurons, suggesting that c-Jun may regulate genes that are important both in the early post-injury period and during later peripheral axonal regeneration. However, neither the mechanism through which c-Jun protein is increased nor the level of its post-injury transcriptional activity in axotomized DRGs has been characterized. To determine whether transcriptional activation of c-Jun occurs in response to nerve injury in vivo and is associated with axonal regeneration, we have assayed axotomized adult rat DRGs for evidence of jun kinase activation, c-Jun phosphorylation, and activator protein-1 (AP-1) binding. We report that sciatic nerve transection resulted in chronic activation of c-Jun amino-terminal kinase-1 (JNK) in L4/L5 DRGs concomitant with c-Jun amino-terminal phosphorylation in neurons, and lasting AP-1 binding activity, with both c-Jun and JunD participating in DNA binding complexes. The timing of JNK activation was dependent on the distance of the axotomy site from the DRGs, suggesting the requirement for a retrograde transport-mediated signal. AP-1 binding and c-Jun protein returned to basal levels in DRGs as peripheral regeneration was completed but remained elevated in the case of chronic sprouting, indicating that c-Jun may regulate target genes that are involved in axonal outgrowth.
Kenney
A M
AM
Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
Kocsis
J D
JD
D000818:Animals; D001369:Axons / Q000502:physiology; D019771:Axotomy; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000502:physiology*; D005260:Female; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D009416:Nerve Regeneration / Q000502:physiology; D009474:Neurons / Q000378:metabolism; D010766:Phosphorylation; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D018808:Transcription Factor AP-1 / Q000378:metabolism*
D016755:Proto-Oncogene Proteins c-jun; D018808:Transcription Factor AP-1; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases